sh: Fix warning about uninitialized value of ramdisk_flags

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
diff --git a/arch/sh/lib/bootm.c b/arch/sh/lib/bootm.c
index 019e8ec..f38d0b0 100644
--- a/arch/sh/lib/bootm.c
+++ b/arch/sh/lib/bootm.c
@@ -103,7 +103,7 @@
 	sh_check_cmd_arg(bootargs, CMD_ARG_RD_DOLOAD, 10);
 	/* Initrd */
 	if (images->rd_start || images->rd_end) {
-		unsigned long ramdisk_flags;
+		unsigned long ramdisk_flags = 0;
 		int val = sh_check_cmd_arg(bootargs, CMD_ARG_RD_PROMPT, 10);
 		if (val == 1)
 				ramdisk_flags |= RD_PROMPT;